Alternatives to Antibiotic Use: Probiotics for the Gut

Author: Reid, Gregor; Friendship, Robert Description: Developed countries are not immune from serious food-borne diseases, and the source is often the intestine of cattle, sheep and poultry livestock. Outbreaks of Escherichia coli 0157, most recently killing people in Ontario, and of salmonella and shigella food poisoning especially during summer months, remind us of the seriousness of the problem. Thus, there is renewed interest in alternative approaches to antibiotics to control bacterial diseases, both in humans and veterinary medicine. Consumers are believed to be concerned not only about bacterial pathogens being…

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The good viruses: viral mutualistic symbioses

Author: Roossinck, Marilyn J. Description: Viruses have traditionally been thought of as pathogens, but many confer a benefit to their hosts and some are essential for the host life cycle. The polydnaviruses of endoparasitoid wasps have evolved with their hosts to become essential. Many of the viral genes are now encoded in the host nucleus. Endogenous retroviruses are abundant in many genomes of higher eukaryotes, and some have been involved in the evolution of their hosts, such as placental mammals. Some mammalian viruses can protect their hosts from infection by…

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Dietary simple sugars alter microbial ecology in the gut and promote colitis in mice

Author: Khan, S., Waliullah, S., Godfrey, V., Khan, M. A. W., Ramachandran, R. A., Cantarel, B. L., Behrendt, C., Peng, L., Hooper, L. V., & Zaki, H. Description: The higher prevalence of inflammatory bowel disease (IBD) in Western countries points to Western diet as a possible IBD risk factor. High sugar, which is linked to many noncommunicable diseases, is a hallmark of the Western diet, but its role in IBD remains unknown. Here, we studied the effects of simple sugars such as glucose and fructose on colitis pathogenesis in wild-type…

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The impact of microbiota on brain and behavior: mechanisms & therapeutic potential

Author: Borre, Y. E., Moloney, R. D., Clarke, G., Dinan, T. G., & Cryan, J. F. Description: There is increasing evidence that host-microbe interactions play a key role in maintaining homeostasis. Alterations in gut microbial composition is associated with marked changes in behaviors relevant to mood, pain and cognition, establishing the critical importance of the bi-directional pathway of communication between the microbiota and the brain in health and disease. Dysfunction of the microbiome-brain-gut axis has been implicated in stress-related disorders such as depression, anxiety and irritable bowel syndrome and neurodevelopmental…

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A century of the phage: past, present and future

Author: Salmond, G. P. C. & Fineran, P. C. Description: Viruses that infect bacteria (bacteriophages; also known as phages) were discovered 100 years ago. Since then, phage research has transformed fundamental and translational biosciences. For example, phages were crucial in establishing the central dogma of molecular biology – information is sequentially passed from DNA to RNA to proteins – and they have been shown to have major roles in ecosystems, and help drive bacterial evolution and virulence. Furthermore, phage research has provided many techniques and reagents that underpin modern biology…

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Antibiotic treatments and microbes in the gut

Author: Macfarlane, S. Description: Antibiotic therapies are important in combating disease-causing microorganisms and maintaining host health. It is widely accepted that exposure of the gut microbiota to antibiotics can lead to decreased susceptibility and the development of multi-drug-resistant disease-causing organisms, which can be a major clinical problem. It is also important to consider that antibiotics not only target pathogenic bacteria in the gut, but also can have damaging effects on the ecology of commensal species. This can reduce intrinsic colonization resistance and contribute to problems with antibiotic resistance, including lateral…

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Induced expression of the heat shock protein genes uspA and grpE during starvation at low temperatures and their influence on thermal resistance of Escherichia coli O157:H7

Author: Zhang, Y.; Griffiths, M.W. Description: Heat shock proteins play an important role in protecting bacterial cells against several stresses, including starvation. In this study, the promoters for two genes encoding heat shock proteins involved in many stress responses, UspA and GrpE, were fused with the green fluorescent protein (gfp) gene. Thus, the expression of the two genes could be quantified by measuring the fluorescence emitted by the cells under different environmental conditions. The heat resistance levels of starved and nonstarved cells during storage at 5, 10, and 37 degrees…

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Serratia marcescens: historical perspective and clinical review

Author: Yu, V.L. Description: SERRATIA MARCESCENS is a bacterium recognized with increasing frequency as a cause of serious infection in man. This micro-organism has a romantic history dating to antiquity, when, because of production of a red pigment, it masqueraded as blood. In this century, this distinctive pigmentation, combined with its apparent low level of virulence, led to its use as a biologic marker. This article will review the more distinctive historical aspects of S. marcescens and discuss its clinical status as an emerging pathogen. Subject headings: Aerosols; Anti-Bacterial Agents/therapeutic…

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Shigella as a foodborne pathogen and current methods for detection in food

Author: Warren, B.R.; Parish, M.E.; Schneider, K.R. Description: Shigella, the causative agent of shigellosis or “bacillary dysentery,” has been increasingly involved in foodborne outbreaks. According to the Centers for Disease Control and Prevention’s Emerging Infections Program, Foodborne Diseases Active Surveillance Network (FoodNet), Shigella was the third most reported foodborne bacterial pathogen in 2002. Foods are most commonly contaminated with Shigella by an infected food handler who practices poor personal hygiene. Shigella is acid resistant, salt tolerant, and can survive at infective levels in many types of foods such as fruits…

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Citrus flavonoid represses Salmonella pathogenicity island 1 and motility in S. Typhimurium LT2

Author: Vikram, A.; Jesudhasan, P.R.; Jayaprakasha, G.K.; Pillai, S.D.; Jayaraman, A.; Patil, B.S. Description: Salmonellosis is one of the leading health problems worldwide. With the rise of drug resistance strains, it has become imperative to identify alternative strategies to counter bacterial infection. Natural products were used historically to identify novel compounds with various bioactivities. Citrus species is a rich source of flavonoids. Naringenin, a flavonone, is present predominantly in grapefruit. Previously we have demonstrated that naringenin is potent inhibitor of cell-cell signaling. The current study was undertaken to understand the…

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